In recent years, cardiovascular diseases, such as hypertension, have become one of the major reasons causing death, and the population having these diseases increases every year. Since hypertension is a chronic disease, the patients have to take anti-hypertension drugs for a long period of time. According to the statistical data of Japan, the market of anti-hypertension drugs is steady at 50 billion yen annually, and the market of health food relating to blood pressure control increased from 1.4 billion yen in 1997 to 7.2 billion yen in 1999. Therefore the demand of the drugs and foods having blood pressure lowering activity in the world increases every year.
Historically, the genus Monascus has been wildly used in preparing traditional Chinese medicine and food, and used as food additives in China. JP 61197524 discloses that the metabolites from the genuses of Aspergillus and Monascus can improve the syndrome of hypertension. Kohama et. al. (Chemical and Pharmaceutical Bulletin, 35, (1987), 2484–2489) found that gamma-aminobutyric acid (GABA) and acetylcholine (Ach) in the fermentation liquid have the effect of lowing blood pressure. JP 62298598 discloses a method for collecting the materials having blood pressure lowering activity. JP 03090031 provides an improved culture medium for Monascus purpureus in increasing the production of the materials having blood pressure lowering activity. JP 2000279163 discloses a food having blood pressure lowering activity prepared from Monascus purpureus, which contains GABA and glucosamine. WO 01/31048 A1 discloses a nitric oxide donor composition prepared by using Monascus purpureus to ferment red rice, which has the effects on vasodilation and lowering blood pressure.
Blanc et. al. (International Journal of Food Micorbiology; 27, (1995), 201–213) found that Monascus purpureus produces a fungal toxin, named citrinin, which caused considerable attention to the safety of the Monascus products. JP 7274978 discloses a mutation method for reducing the amount of citrinin (lower than 1 ppm) in the production of red pigment. However, the activity of lowering blood pressure was not disclosed thereby.
The microorganisms of the genus of Monascus have been widely used in producing the material for lowering blood pressure, but the products thereof contain a high amount of citrinin. Therefore, the safety of the fermentation product is of concern.